134  Gleanings  from  the  German\Journals,  {^"^-^tr'^l^o!"^- 
of  pure  concentrated  sulphuric  acid  and  heat  slowly  to  boiling,  and 
until  the  iron  is  completely  dissolved,  when  the  precipitated  copper  will- 
alone  remain,  contaminated  with  a  little  carbon.  Wash  it  repeatedly  by 
decantation  with  water,  afterwards  with  alcohol,  absolute  alcohol  and 
ether,  dry  the  flask  quickly  by  heat,  weigh,  and  from  the  weight  of  the 
copper  subtract  the  carbon  of  the  powdered  iron  (about  O'Oi  gram). 
Since  the  difference  between  the  weight  of  this  precipitated  copper  and 
the  total  weight  of  the  metallic  copper  (1*271  gram)  contained  in  the 
5  grams  of  crystallized  sulphate  equals  the  quantity  of  the  copper^ 
which  was  precipitated  by  the  metallic  iron  contained  in  i  gram  of  the 
reduced  iron,  the  percentage  of  the  unoxidized  metal  is  readily  deter- 
mined from  the  ascertained  weight,  and  the  relation  between  the  atomic 
weights  of  copper  and  iron.  The  number  of  centigrams  of  iron  cal- 
culated from  the  copper  which  was  precipitated  in  the  first  part  of  the 
process  indicates  directly  the  percentage  of  the  metallic  iron  contained 
in  the  reduced  iron. — Archiv  d.  Pharm.^  Dec,  1879,  p.  508. 
Detection  of  Ammonia  in  Water. — Ammonia  is  usually  present  in 
water  as  carbonate,  but  frequently  in  such  small  quantities  that  it  can- 
not be  detected  by  the  ordinary  tests.  In  such  cases  Hager  ascertains 
its  presence  by  mixing  2  to  3  liters  of  the  water  with  20  drops  hydro- 
chloric acid,  evaporating  to  dryness,  dissolving  the  residue  in  10  or  15; 
cc.  distilled  water,  filtering,  and.  applying  Bohlig's  test,  which  consists 
in  adding,  first,  5  drops  of  solution  of  corrosive  sublimate  (i  part  in  30 
parts  of  water),  and  then  5  drops  of  solution  of  potassium  carbonate  (i 
part  in  50  parts  of  water),  when  a  cloudiness  indicates  the  presence  of 
ammonia. — Pharm.  Centralh.^  Dec.  25,  1879,  p.  474. 
An  Acid  and  a  Neutral  Ammonium  Valerianate  are  distinguished 
by  Hager,  who  reports  that  the  commercial  ammonium  valerianate  is 
always  the  acid  salt^  which  consists  usually  of  handsome  crystals,  having 
an  acid  taste  and  reaction,  and  readily  decomposed  unless  kept  in  tightly 
stoppered  bottles.  The  decomposition  is  proved  by  its  penetrating  odor 
and  the  strongly  rotating  motion  of  the  crystals  when  thrown  on  cold 
water  ;  this  rotation  is  an  excellent  test  for  identifying  the  salt. 
Neutral  Jmmoniu?n  Valerianate  is  obtained  with  the  greatest  difficulty 
in  prismatic  crystals  by  the  action  of  anhydrous  ammonia  on  the  mono- 
hydrated  acid  at  a  low  temperature  ;  the  crystals  of  the  neutral  salt 
liquefy  even  at  a  moderate  temperature,  without,  however,  absorbing 
moisture.  Hager  thinks  that  physicians,  when  ordering  ammonium 
valerianate  in  pills  or  in  any  other  solid  shape,  want  the  acid  valerian- 
